I recently got my first camera, a Minolta x 700. After about half a roll of film, I realized that the preview button did nothing, regardless of being in program or aperture modes, and regardless of the aperture set. I took the lens off and made sure the arm that's moved by the button moved freely, and the lever on the lens moves freely as well, but even manually moving the arm on the lens and changing the aperture ring, I don't see anything physically happening looking through either end of the lens. I assume I should see the size of the aperture close as the f number gets higher? With the cost of these lenses, I assume a repair isn't quite worth it? After I get a different lens, would it be worth trying to take apart the lens to see what's stuck inside? Would I even be able to get that deep in the lens? At that point, I'd basically count the lens as garbage, and if I get it working, great! I've got a limited amount of optic knowledge, I was a Canon trained service technician for their printers and copy machines, and some of the older machines still has optical scan beds.